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Formic acid is one of the key components in green chemistry being involved in energy storage, production of chemical intermediates and fuel components. Therefore the knowledge of its stability is of crucial importance and a systematic study of its decomposition is needed. The kinetics of formic acid decomposition to hydrogen and carbon dioxide was investigated in a laboratory-scale fixed bed reactor at 150–225 °C and atmospheric pressure. Palladium nanoparticles deposited on porous active carbon Sibunit were used as the heterogeneous catalyst. The catalyst was characterized by nitrogen physisorption and high-resolution transmission electron microscopy. The average palladium nanoparticle size was 5–6 nm. The impacts of mass transfer resistance and formic acid dimerization were negligible under the reaction conditions. Prolonged experiments revealed that the catalyst had a good stability. Hydrogen and carbon dioxide were the absolutely dominant reaction products, whereas the amounts of carbon monoxide and water were negligible. The experimental data were described with three kinetic models: first order kinetics, two-step adsorption-reaction model and multistep adsorption-decomposition model of formic acid. The multistep model gave the best description of the data.

The article represents a new production method based on polylactic acid for electronic devices. The originality of the proposed method is the replacement of environmentally unfriendly binders currently used in the manufacture of printed circuit boards with biodegradable polymers. We focused on materials based on renewable raw materials, which can be completely recycled to safe chemicals or reused without deep recycling in chemical or biochemical industries. Also, the proposed material biodegrades naturally into environmental substances. This approach has great potential for practical industrial uses, especially in the light of the “green chemistry” and “circular economy” concepts. Besides, the described materials are a promising base for creating new composite materials for biodegradable electronics.

Copper nanoparticles show considerable antibacterial, anti-fungal and related effects in comparison with bulk CuO and have been explored for their biological applications. In this work green synthesis approach was adopted to synthesize CuONps utilizing Syzygium aromaticum bud extract. CuONps showed a sharp band around 298 nm in UV–Vis spectrum, affirming their formation. The average size of synthesized CuONps was inspected by Debye-Scherrer equation using PXRD spectrum and was found 70 nm. Interaction study of CuONps with Calf-Thymus DNA have been investigated which has given significant results. The CuONps have also shown 20% DNA cleavage activity against E.coli DNA.

Biosynthesis of zinc oxide nanoparticles (ZnO NPs) using the peel extract of Hylocereus undatus (dragon fruit) was carried out for the first time by a green chemistry approach. The peel used for this study, act as a reducing and capping agent for synthesizing ZnO NPs from the precursor salt. The synthesized nanoparticles were characterized by UV–Visible Spectroscopy, Scanning Electron Microscopy (SEM), Energy Dispersive analysis of X-ray (EDAX) and Fourier transform infrared spectroscopy (FT-IR). The anti-microbial activity of ZnO NPs were assessed against the microbial pathogens and compared with the crude extract of H. undatus. The synthesized nanoparticles showed more effective against gram positive (Bacillus subtilis) bacteria than gram negative (Escherichia coli, Klebsella Pneumoniae and Pseudomonas aeruginosa), and moderate activity was found against C. albicans. It indicates the biomedical capability of ZnO NPs.

One of the most popular building blocks for producing organic semiconductors is 2,7-dibromo-9H-carbazole and its derivatives. Building blocks based on 9H-carbazole are among the most expensive building blocks. The article presents new, highly effective, and “green” methods for the synthesis of 2,7-dibromo-9H-carbazole and its derivatives under microwave irradiation. The use of a flow-type microwave reactor significantly reduced the synthesis time. The methods described differ in efficiency, simplicity, performance, and a significant reduction in time compared to classical methods. The research was conducted in accordance with the principles of green chemistry.

Graphical abstract We describe the total flow synthesis of the widely prescribed anti-inflammatory COX-2 inhibitor Celecoxib from 2-bromo-3,3,3-trifluoropropene, as a convenient and available trifluoromethyl building block, to generate trifluoropropynyl lithium and to trap it immediately with an aldehyde. Oxidation of the obtained alcohol into ketone followed by condensation with 4-sulfamidophenylhydrazine afforded the targeted drug with full regioselectivity. It is noteworthy that the quality of these flow reactions (50% overall yield within 1 h cumulated residence time over 3 steps) directly furnished the target API and intermediates with excellent purity. Supplementary Information The online version contains supplementary material available at 10.1007/s41981-021-00205-x.

The plasmonic photocatalyst of Pd supported on graphitic carbon nitride (Pd/g-C3N4) exhibits excellent catalytic activity in photo-induced hydrogenation of biomass-based aldehydes with environmental benign reagents of formic acid (HCOOH) as proton source and triethylamine (TEA) as sacrificial electron donator. The chemical and configurational properties of the Pd/g-C3N4 were systematically analyzed with XRD, TEM and XPS. Under optimized conditions, 27% yield of furfuryl alcohol with the corresponding turnover frequency (TOF) around 3.72 h−1 were obtained from furfural and TEA-HCOOH under visible-light irradiation by using Pd/g-C3N4. Our research additionally reveals that Pd atom is the true catalytic active site for the hydrogenation and the photo-promoted reduction mainly occurs through noble metal nanoparticles (NPs)-induced effect of surface plasmon resonance (SPR). The photo-catalytic system of Pd/g-C3N4 thus demonstrates a green and effective method for the hydrogenation of biomass-based aldehydes with sustainable solar energy as a driven force.

Lignin is a potential renewable raw material for synthesis of aromatic molecules and materials. Particularly, Kraft-type lignins are abundantly available as a byproduct of wood and paper industries. Currently, there are practically no valuable products made using this highly complex polymer. Within this work, we have investigated the straightforward, high-yield depolymerization of two different technical lignins (Indulin AT and alkaline lignin) using only a mixture of green short-chain (C-1-C-3) alcohols and water as solvents. As shown here, at a temperature of 220 degrees C, autogenous pressure, and isopropanol/water as a co-solvent medium, it is possible to cleave Kraft lignin without char-forming side reactions. The obtained so-called "light" oil contains guaiacol-based monomeric units of 23 wt % yield together with liquid oligomers of 13 wt % yield combining liquid-liquid and solid-liquid extraction. Two-dimensional nuclear magnetic resonance analysis of lignin residues showed that the isopropanol/water treatment caused a marked breakdown of the intermolecular beta-O-4 and beta-beta bonds; thus, the depolymerization produced monomers and lignin residues with lower molecular weight. The results suggested a synergistic effect between isopropanol and water. No sign of repolymerization reactions could be observed with this process.

Green chemistry using ficus leaf extract has become an ecological technique and was used for preparing zerovalent iron nanoparticles (nZVFe). The Ficus benjamina nano-zero-valent iron (FB-nZVFe) was characterised by scanning electron microscopy and Fourier transform infrared spectroscopy. The Orange G removal percentage (10 mg/l) reached 73% (0.3 g/l, 45 min and pH 4). The adsorption data agree more with the Langmuir model (R 2 = 0.9993), q max = 27.66 mg/g. The kinetic results showed that Orange G uptake follows a pseudo-second-order model. Langmuir isotherm and pseudo-second-order kinetic studies are more appropriate in linear and non-linear models. In general, F. benjamina nZVFe is a promising green material for Orange G removal. The IBM SPSS Statistics software was used to investigate the effect of different operational parameters, they were found to account for more than 98% of the variables affecting the removal procedure.

The current research work focuses on the conventional bio-catalysed synthesis of amyl levulinate with immobilized Candida antarctica lipase B in the absence of a toxic solvent. The green catalyst and solvent free system offered considerable benefits like mild and gentle condition requirement, lesser-energy demand, easy down-streaming and reusability of the biocatalyst. The process parameters were examined, and the maximum conversion (73.2%) was obtained under the optimum condition of 50℃ temperature, 1:3 molar ratio of levulinic acid to amyl alcohol using 0.8% (w/v) biocatalyst at 250 rpm speed. The immobilized lipase was characterized by SEM, BET, XRD, FTIR and amyl levulinate was characterized by FTIR and GC-MS analysis. The enzyme lipase was effectively reused till 5 cycles for the formation of ester. The thermodynamic parameters (ΔH, ΔG, and ΔS) and energy of activation (Ea) were determined for the assessment of energy requirement. The activation energy was determined to be 48.42 kJ/mol. The research protocol strikes the development of biocatalytic synthetic route of amyl levulinate without using any toxic solvent, which may contribute to green chemistry approach.

This research explores the possibilities and limitations of WD-XRF, applied as a method for quantification of 20 elements in plant material, using spiked cellulose standards for calibration. Three different analytical methods were investigated: 1) standards created from pure spiked cellulose; 2) spiked cellulose mixed with 20% of binder and 3) spiked cellulose applied as a thin layer on an inert carrier. Sensitivity, linearity, limit of detection, limit of quantification, repeatability, intralaboratory reproducibility, and accuracy were determined and compared. The accuracy of the investigated methods was tested by analysis of standard reference materials and comparison with other routinely used analytical techniques (ICP-OES and ICP-MS). The comparison included real plant samples which were collected from the environment characterized by different pollution levels. The accuracy of the semiquantitative standardless method was also considered and compared with other investigated methods. Tested methods can be very precise, with good intralaboratory reproducibility over wide linear range. Supplementary material: [https://cherry.chem.bg.ac.rs/handle/123456789/4615] This is the peer-reviewed version of the article: Orlić, J., Gržetić, I., Goessler, W., Braeuer, S., Čáslavský, J., Pořízka, J.,& Ilijević, K.. (2021). Artificial cellulose standards as calibration standards for wavelength-dispersive X-ray fluorescence analysis of elements in plant samples. in Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms Elsevier., 502, 106-117. [https://doi.org/10.1016/j.nimb.2021.06.012]

Research in green chemistry has recently focussed on designing reactions in water as a safe solvent, calling for catalysts that operate in aqueous solutions. In particular, supramolecular metal nanoparticles have been synthesized by associating macrocyclic compounds with transition metal nanoparticles, to produce water-dispersible catalytic systems of high performance and molecular recognition ability. Here we review methods for stabilizing catalytically active metal nanoparticles in cyclodextrin-based systems. Indeed, cyclodextrins form inclusion complexes with molecules of appropriate size and shape, and the presence of hydroxyl groups enables coordination with metal ions. Representative examples show increasing stability, recyclability and catalytic activity. We present 1) the synthesis, characterization and catalytic behaviors with focus on the development of metal nanoparticles in solvent-dispersed form or immobilized onto supports in the presence of cyclodextrins or their derivatives; 2) the multi-functional role of cyclodextrins capable of acting as reducing agents, stabilizing/dispersing agents or mass transfer promoters; and 3) the design of more sophisticated catalytic systems, in which the cyclodextrin is a supramolecular host with dynamic equilibrium.

Coumarin derivatives are essential scaffolds in medicinal and synthetic chemistry. Compounds of this class have shown important activities, such as anticancer and antiparasitic, besides the commercially available drugs. These properties led to the development of efficient and greener synthetic methods to achieve the 2H-chromen-2-one core. In this context, the advances in asymmetric organocatalyzed synthesis of coumarin derivatives are discussed in this review, according to the mode of activation of the catalyst.

A highly efficient and stable heterogeneous coordination polymer (CP) was successfully prepared by hydrothermal combination of silver and 4,6-diamino-2-pyrimidinethiol. The prepared coordination polymer was characterized by FT-IR, XRD, TGA, SEM, EDX, X-ray mapping and Nitrogen adsorption–desorption analysis. The prepared Ag–CP exhibit excellent catalytic activity in multicomponent Hantzsch synthesis of polyhydroquinolines under mild reaction conditions in relatively short reaction times. The heterogeneity of the catalyst was confirmed by the hot filtration test; also, the catalyst was reused for at least four times under the optimized reaction conditions without any significant loss of its catalytic activity.

Catalytic hydrogenation of furfural to furfuryl alcohol is an important upgrading process for valorization of biomass-derived furanyl platform molecules. However, selective hydrogenation of α,β-unsaturated aldehydes like furfural to the corresponding alcohols at ambient pressure remains challenging in sustainable chemistry. Till date heterogeneous Au hydrogenation catalyst has been scarcely reported for this reaction due to the low reactivity of Au for H2 dissociation. In this work, we showed that Au nanoparticles (loading: 0.2 wt%) with a mean size of about 3 nm supported on Cu-doped Al2O3 can efficiently hydrogenate furfural to furfuryl alcohol in liquid phase at ambient pressure. We demonstrated that doping a small amount of Cu (2 mol%) to γ-Al2O3 may modify the Lewis acidity-basicity of Al2O3 and simultaneously induce the presence of sufficient Cu+ species on surface, which facilitated the hydrogen transfer from i-PrOH to furfural. Moreover, we observed an enhanced reactivity of Au toward molecular H2 via cooperation with the Lewis acidic-basic Cu2O-Al2O3 support. Hence, 100% yield to furfuryl alcohol with a productivity of 0.98 gFA⋅h−1⋅gcat.−1 at 120 °C and 0.1 MPa H2 can be obtained. The prepared Au/Cu-Al2O3 catalyst was found reusable and was effective to the concentrated furfural solution, as well as several typical unsaturated aldehydes.

Background Low temperature bonding is the key for developing advanced electronic packaging technique. While Cu is regarded as a promising material for interconnects with high conductivity, the oxidation issue during processing needs to be solved. Methods In this study, Cu-to-Cu direct bonding was achieved at low temperature without applying pressure by a green chemical method. Synthesized Cu nanoparticles (NPs) without capping agents were mixed with polyethylene glycol (PEG). Significant findings An iterating mechanism is proposed as Cu oxide catalyzing the decomposition of PEG, and the decomposed products further reduce the Cu oxide. Particle size and size distribution of Cu NPs were simply controlled by pH value of the reducing solution. A random close packing model proves that packing density of the pre-sintered Cu NPs directly correlates to bonding strength. Ductile fracture surface confirms the realization of well-sintered joints by a green process that can be applied to devices.

ω-Transaminases (ω-TA) are attractive biocatalysts for the production of chiral amines from prochiral ketones via asymmetric synthesis. However, the substrate scope of ω-TAs is usually limited due to steric hindrance at the active site pockets. We explored a protein engineering strategy using computational design to expand the substrate scope of an (S)-selective ω-TA from Pseudomonas jessenii (PjTA-R6) toward the production of bulky amines. PjTA-R6 is attractive for use in applied biocatalysis due to its thermostability, tolerance to organic solvents, and acceptance of high concentrations of isopropylamine as amino donor. PjTA-R6 showed no detectable activity for the synthesis of six bicyclic or bulky amines targeted in this study. Six small libraries composed of 7-18 variants each were separately designed via computational methods and tested in the laboratory for ketone to amine conversion. In each library, the vast majority of the variants displayed the desired activity, and of the 40 different designs, 38 produced the target amine in good yield with >99% enantiomeric excess. This shows that the substrate scope and enantioselectivity of PjTA mutants could be predicted in silico with high accuracy. The single mutant W58G showed the best performance in the synthesis of five structurally similar bulky amines containing the indan and tetralin moieties. The best variant for the other bulky amine, 1-phenylbutylamine, was the triple mutant W58M + F86L + R417L, indicating that Trp58 is a key residue in the large binding pocket for PjTA-R6 redesign. Crystal structures of the two best variants confirmed the computationally predicted structures. The results show that computational design can be an efficient approach to rapidly expand the substrate scope of ω-TAs to produce enantiopure bulky amines.

The exploitation of visible-light active photocatalytic materials can potentially change the supply of energy and deeply transform our world, giving access to a carbon neutral society. Currently, most photocatalysts are produced through low-ecofriendly, energy dispersive, and fossil-based synthesis. Over the last few years, research has focused on the development of innovative heterogeneous photocatalysts by the design of sustainable and green synthetic approaches. These strategies range from the use of plant extracts, to the valorization and recycling of metals inside industrial sludges or from the use of solventless techniques to the elaboration of mild-reaction condition synthetic tools. This mini-review highlights progresses in the development of visible-light-active heterogeneous photocatalysts based on two different approaches: the design of sustainable synthetic methodologies and the use of biomass and waste as sources of chemicals embedded in the final photoactive materials.

A three-step batch-flow hybrid process has been developed for an expeditious synthesis of the enynol key intermediate of antifungal terbinafine. This procedure involves consecutive organometallic steps without the necessity of any in-line purification: after a metalation by n-butyllithium, a selective addition of the lithium salt was elaborated followed by a Grignard reaction resulting in a high yield of 6,6-dimethylhept-1-en-4-yn-3-ol. Moreover, as an alternative to tetrahydrofuran, cyclopentyl methyl ether was used as solvent implementing a safe, sustainable, yet selective synthetic process. Even on a laboratory-scale, the optimized batch-flow hybrid process had a theoretical throughput of 41 g/h. Furthermore, the newly developed process provides an efficient synthesis route to the key-intermediate, while making acrolein obsolete, minimizing side-products, and enabling safe and convenient scale-up.

Purpose: The chemistry society has activated to expand new chemistry that is less destructive to the environment and human health. This approach has extensive interest and designated as green chemistry, environmentally friendly chemistry, clean chemistry, and atom economy. Methodology: There is advancement toward involved chemistry with the facts and do not prevent the properties of the target compound or the efficacy of particular solvents or reagents. The use of chemistry in a way that maximizes benefits while reducing adverse effects has come to be green chemistry. Main findings: Reduce the use and formation of harmful products or by-products. Presently maximum pollution to the environment is caused by some chemical industries. So, need to design and develop synthetic methods in such a way that the waste products are lowest and have no effect on the environment and their handy disposal. Applications of the work: Green chemistry plays a vital role in pharmaceuticals for developing new drugs which are less toxic, more effective with low side effects. The novelty of the work: The industries performing manufacturing using green synthesis methods to carrying out their productions have positive impacts on environmental sustainability. This review is looking ahead at longer-term challenges and prospects in research, industrial applications, and education.

The spread of antibiotic-resistant pathogenic bacteria is an increasing health issue worldwide. A possible origin of antibiotic resistance could be the persistence of antibiotics in the aquatic environment. To tackle this problem, restricted control of application of antibiotics in human and veterinary medicine has been proposed. However, these measures do not prevent the spreadof antibiotic resistance but may delay the process, since antibiotics are still continuously emitted into the environment and many persist there. Derived from ciprofloxacin (CIP), CIP-Hemi, a fluoroquinolone with improved environmental properties, was developed following the benign by design approach and using insilico and in vitro methods. CIP-Hemi was designed to maintain its required metabolic stability (human liver microsomes, intestinal microsomes, blood plasma) and antibiotic activity (MIC in the μg mL−1 range) against the target while transforming into an inactive fragment (CIP-d-CP) and a degradable linker present under acidic conditions, e.g., after excretion or when released into theenvironment. Moreover, CIP-Hemi and CIP-d-CP showed weaker cytotoxic and mutagenic or genotoxic effects compared to the parent compound CIP and therefore underline the feasibility of CIP-Hemi as a viable antibiotic drug candidate, demonstrating benign by design as a promising approach.

Uracil compounds participate in a wide range of biological activities; however, reports on their synthesis using heterogeneous catalysts are scarce. In this work, the multicomponent synthesis of uracil derivatives assisted by layered double hydroxides (LDH) was studied under green chemistry conditions. The incorporation of Ni2+ or Co2+ was successfully performed by co-precipitation method. The yields to uracil derivatives are associated with the presence of weak basic sites and a better interaction of the reagents when the reaction is carried out in solvent-free conditions. The reaction pathway involves the formation of an enone between benzaldehyde and ethyl cyanoacetate, and subsequent reaction with urea, which is assisted by the presence of a basic catalyst. The scope of this synthesis is illustrated with nine examples.

Novel nano-ordered 1,1,3,3-tetramethylguanidine-functionalized melamine (Melamine@TMG) organocatalyst was prepared and adequately identified by various techniques including FTIR, EDX, XRD and SEM spectroscopic or microscopic methods as well as TGA and DTG analytical methods. The Melamine@TMG, as an effective multifunctional organocatalyst, was found to promote smoothly the three-component synthesis of 1,2,4-triazoloquinazolinone derivatives using cyclic dimedone, 3-amino-1,2,4-triazole and different benzaldehyde derivatives in EtOH at 40 °C. This practical method afforded the desired products in high to excellent yields (86–99%) and short reaction times (10–25 min). The main advantages of this new method are the use of heterogeneous multifunctional nanocatalyst, simple work-up procedure with no need for chromatographic purification, highly selective conversion of substrates and recyclability of the catalyst, which could be used in five consecutive runs with only a small decrease in its activity.

Fe3O4/g-C3N4/Alginate-Ag nanocomposite as a novel and effective nanocatalyst was successfully prepared. This nanocomposite was fully characterized using several techniques such as X‐ray diffraction (XRD), field emission scanning electron microscopy with energy dispersive spectroscopy (FESEM-EDS), transmission electron microscopy (TEM), and Fourier transform infrared spectroscopy (FTIR). In addition, the catalytic activity of this novel and characterized nanocatalyst was investigated in the regioselective synthesis of 1,4-disubstituted 1,2,3-triazoles via click reaction and A3 and KA2 coupling reaction in aqueous media. The prepared nanocatalyst was simply recovered by using an external magnet and reused for several times with a slight loss of catalytic activity.

In Earth matter evolution, the deoxygenation process plays a central role as plant and animal remains, which are composed by highly oxygenated molecules, were gradually deoxygenated into hydrocarbons to give fossil fuels deep in the Earth crust. The understanding of this process is becoming crucial to the entire world and to the sustainable development of mankind. This review provides a brief summary of the extensive deoxygenation research under mild, potentially sustainable conditions. We also summarize some challenges and opportunities for potential deoxygenation reactions in the future.

FTIR spectroscopic study is performed in 4000 – 400cm−1wavenumber rangeon pure Propanol(PRO), pure o-xylene (OXY), pure m-xylene(MXY), pure p-xylene(PXY) and their binary solutions (SS1 = 0.2 PRO + 0.8 OXY/MXY/PXY, SS2 =0.4+0.6 , SS3 = 0.6 + 0.4 and SS4 = 0.8 + 0.2)at various mole fractions. It was observed that neat propanol liquid appearsto be multimer especially as cyclic tetramer and involve in classical and non-classical hydrogen bond interactions with the three xylene isomers in all the binary solutions.

Physicochemical studies of amino acids in an aqueous medium can provide significant knowledge about the stabilization mechanism of proteins.In this study, the viscosity (ƞ), surface tension (γ), density (ρ) and the specific conductance (κ) measurements have been carried out for amino acid L-lysine (0.02 to 1.6M) in aqueous solutions at 293.15K. The experimental data shows that there is an increase in the viscosity, surface tension, conductance, and density of the L-lysine with and without glucose, sucrose, sodium chloride, and potassium chloride with concentration.The solute-solute and solute-solvent interactions have been discussed on the basis of all physicochemical parameters.

There is a need to find alternative solvents for electrospinning that are less hazardous and more environmentally safe than the Class II solvents currently used. We characterized poly(lactic-co-gly...

Ammonia (NH3) is one of the key commercial chemicals and carbon-free energy carriers. It is mainly made by Haber-Bosch process under high temperature and high pressure, which consumes huge amount of energy and releases large amounts of CO2. Developing sustainable approaches to its production is of great importance. Powered by a renewable electricity source, electrochemical N2 reduction reaction (NRR) and nitrate reduction reaction (NITRR) are potential routes to synthesize NH3 under ambient conditions. This review summarizes major recent advances in the NRR and NITRR, especially for several years. Some fundamentals for NRR and NITRR are first introduced. Afterward, the design strategies of nanocatalysts are discussed, mainly focusing on nano-structure construction/nanoconfinement, doping/defects engineering and single-atom engineering. Finally, the critical challenges remaining in this research area and promising directions for future research are discussed.

Coupled catalysis using a riboflavin-derived organocatalyst and molecular iodine successfully promoted the aerobic oxidation of thiols to disulfides under metal-free mild conditions. The activation of molecular oxygen occurred smoothly at room temperature through the transfer of electrons from the iodine catalyst to the biomimetic flavin catalyst, forming the basis for a green oxidative synthesis of disulfides from thiols.

Liquid-phase selective oxidation of alcohols to aldehydes using molecular oxygen as an oxidant is one of the most important transformations in organic synthesis and green chemistry. In this work, nitrogen-containing ordered mesoporous materials (NOMCs) were prepared and utilized as supports to load vanadia. The physical and chemical properties of the synthesized VxOy/NOMC materials were characterized by N2 adsorption–desorption, XRD, TEM, Raman, and XPS. The characterization results exhibited that NOMC could well disperse vanadia species and there was a steady interaction between V and N of NOMC. In selective oxidation of benzyl alcohol using oxygen as an oxidant, the synthesized VxOy/NOMC materials showed good and stable catalytic performance, affording a maximum yield of benzaldehyde up to 80% at 95 °C.

Zirconium-based metal-organic framework materials (Zr-MOFs) have more practical usage over most conventional benchmark porous materials and even many other MOFs due to the excellent structural stability, rich coordination forms, and various active sites. However, their mass-production and application are restricted by the high-cost raw materials, complex synthesis procedures, harsh reaction conditions, and unexpected environmental impact. Based on the principles of "Green Chemistry", considerable efforts have been done for breaking through the limitations, and significant progress has been made in the sustainable synthesis of Zr-MOFs over the past decade. In this review, the advancements of green raw materials and green synthesis methods in the synthesis of Zr-MOFs are reviewed, along with the corresponding drawbacks. The challenges and prospects are discussed and outlooked, expecting to provide guidance for the acceleration of the industrialization and commercialization of Zr-MOFs.

Vibrational spectroscopy such as Fourier-transform infrared (FTIR), has been used successfully for soil diagnosis owing to its low cost, minimal sample preparation, non-destructive nature, and reliable results. This study aimed at optimizing one of the essential settings during the acquisition of FTIR spectra (viz. Scans number) using the standardized moment distance index (SMDI) as a metric that could trap the fine points of the curve and extract optimal spectral fingerprints of the sample. Furthermore, it can be used successfully to assess the spectra resemblance. The study revealed that beyond 50 scans the similarity of the acquisitions has been remarkably improved. Subsequently, the effect of the number of scans on the predictive ability of partial least squares regression models for the estimation of five selected soil properties (i.e., soil pH in water, soil organic carbon, total nitrogen, cation exchange capacity and Olsen phosphorus) was assessed, and the results showed a general tendency in improving the correlation coefficient (R2) as the number of scans increased from 10 to 80. In contrast, the cross-validation error RMSECV decreased with increasing scan number, reflecting an improvement of the predictive quality of the calibration models with an increasing number of scans.

This study describes the development of a nano-titanium dioxide (TiO2)-based composite of starch-co-poly(acrylamide) (St-g-PAM) copolymer. The graft copolymer was characterised by Fourier transform infrared analysis, thermal gravimetric analysis (TGA), field emission scanning electron microscopy and X-ray diffraction. It was confirmed that acrylamide was grafted over starch successfully. Also, the effects of pH, initiator dosage, temperature and time on grafting percentage and efficiency were investigated. The synthesised titanium dioxide nanoparticle successfully enhancing the thermal and biological properties of a native copolymer was confirmed by TGA and biological assay. This titanium dioxide nanocomposite starch-co-poly(acrylamide) (titanium dioxide/St-g-PAM) showed some important properties, such as plant growth regulation, and acted as a superabsorbent polymer with excellent thermal properties and antibacterial activity. The synthesised titanium dioxide nanoparticle is biodegradable and environment-friendly and accomplished the concept of green chemistry.

Hollow carbon spheres (HCSs) have attracted tremendous interest in recent years due to their intriguing structure-induced physicochemical properties and significant potential for numerous applications. However, the preparation of HCSs with precise structural control using a simple and scalable strategy remains challenging. In this work, hollow carbon particles having a well-defined spherical morphology were successfully produced using a green, economical, and facile spray drying method together with a carbonization process. Kraft lignin was employed as the carbon precursor in place of lignosulfonate with potassium hydroxide (KOH) as an activation agent. The high specific surface area (1536.5–2424.8 m2 g−1) with micro-mesoporous structure of HCSs can be easily tuned by controlling the mass ratio of KOH to carbon precursor. The KOH-to-lignin mass ratios were utilized below 1.5, lower than those in previous studies typically used higher than 3, which was in accordance with green chemistry principles. In addition, these HCSs have applications as electrode materials in supercapacitors for energy storage devices. With the great achievements and continuous efforts in this important field, these results suggest that our approach will open a new path for the development of advanced carbon materials and high value-added utilization of Kraft lignin as a promising material for potential applications.

Electrochemical (EC) reduction of graphene oxide (GO) serves as a green chemistry pathway to produce reduced GO (rGO). However, the mechanistic understanding of this process is still limited due to the structural complexity of GO-based materials. In the present study, we employ an inductive approach that consists of investigating the structures afforded by alternating EC reduction and oxidation steps to elucidate the electrochemical reduction reactions in aqueous solution. The initial EC reduction of chemically derived GO mainly converts epoxides (C–O–C) to COH/CH pairs. Simultaneously, carbon-centered radicals (C•) are eliminated. Subsequent EC oxidation does not result in restoration of epoxides but reverse dehydrogenation and radical formation. The second EC reduction and oxidation cycle involves reversible C–H formation coupled with radical elimination, suggesting that C• serves as an active site for the hydrogenation. As a result of this study, COH–CH is revealed as a plausible characteristic structure in electrochemically derived rGO. The reversible radical hydrogenation reaction can offer an effective route to manipulate the chemical reactivities of GO-based materials. We demonstrate that the electrons transferred by EC reduction can delocalize in the rGO to some extent, activating the pseudocapacitance that probably originates from COH.

Because of their peculiar nitrogen-rich structure, carbon nitrides are convenient polydentate ligands for designing single-atom-dispersed photocatalysts. However, the relation of catalysts textural properties with their photophysical properties and as a result activity in photocatalytic applications is rarely elaborated. Herein we report the preparation and characterization of a series of single-atom heterogeneous catalysts featuring highly-dispersed Ag and Cu species on mesoporous graphitic C3N4. We show that adjustment of materials textural properties and thereby metal single atoms coordination mode enables ligand-to-metal (LMCT) or ligand-to-metal-to-ligand charge transfer (LMLCT), a property tha was long speculated in single-atom catalysis but never observed. We employ the developed materials in the degradation of organic pollutant under irradiation with visible light. Kinetic investigations under flow conditions show that single atoms of Ag and Cu decrease the amount of toxic organic fragmentation products, while leading to a higher selectivity towards full calcination. The results correlate with the selected mode of charge transfer in the designed photocatalysts and provide a new understanding of the surface state of single-atom catalysts. The concepts can be exploited further to rationally design and optimize other single-atom materials.

Especially, most papers have reported an increase in antibiotic resistance (AR) bacterial infections during the COVID-19 pandemic. Because of the outbreak of the SARS-CoV-2, antimicrobial resistance (AMR) should be controlled and reduced. Researchers have reported that the adsorption technique is an sufficient procedure for separating drugs such as antibiotics from aqueous solutions. The prepared of ZnO/BaTiO3 nanocomposite using Elaeagnus Angustifolia L. leaf extract was successfully obtained using green route. The synthesized nanocomposite was interacted with ciprofloxacin hydrochloride (CPF) to aim at eliminating the antibiotic from aqueous solutions. The incorporation of Elaeagnus Angustifolia leaf extract onto ZnO/BaTiO3 proved a sustainable chemistry study. Hence, this study indicated that green nanoparticles include neither the use of hazardous chemicals nor toxic chemicals. FTIR, XRD, and SEM-EDX analyses were applied to give information about the structural properties of the green nanocomposite. Box-Behnken design (BBD) was executed by response surface methodology (RSM) to gain optimal conditions. The effect of pH, initial concentration of CPF, and nanocomposite dose on CPF-nanocomposite interaction was examined. The experimental findings of adsorption study revealed that the optimal adsorption capacity of CPF onto ZnO/BaTiO3 was found as 125.29 mgg-1 under optimal conditions (adsorbent dose: 3.00 mg, pH value of solution: 9.88, initial concentration CPF: 49.63 mgL-1).

The physio-chemical properties of metallic nanoparticles are different from their corresponding bulk material. Synthesizing stable zero valent copper nanoparticles is a challenge since they get oxidized easily. This paper discusses both the batch and continuous synthesis of copper nanoparticles using a polyol process in the absence of an inert atmosphere. The nanoparticles were synthesized using copper amine complex as a precursor, ascorbic acid as a reducing agent, and polyvinyl pyrrolidone as a capping agent. UV-Vis spectra confirmed that particles from a continuous synthesis had better Localized Surface Plasmon Resonance (LSPR) peak than those from batch synthesis. At 120 °C, nanoparticles in the continuous process could be synthesized at a residence time of 1 min in contrast to the batch reactor, which needed a reaction time of 4 min. The nanoparticles synthesized were of size 1.5–6 nm. Those synthesized in continuous mode were stable for 10 days as compared to those synthesized in batch mode.

Tannic acid‐functionalized silica‐coated Fe3O4 nanoparticles (Fe3O4@SP@TA) were synthesized and characterized by X-ray spectroscopy (EDX), X-ray powder diffraction (XRD), field emission scanning electron microscope (FE-SEM), transmission electron microscope (TEM), vibrating sample magnetometry (VSM) and Fourier transform infrared spectroscopy (FT-IR). Fe3O4@SP@TA supply an eco-friendly procedure for the synthesis of some novel 2-aryl-quinazolinones through one-pot reaction of various synthetized azo-linked benzaldehyes, isatoic anhydride and glycine in accordance with green chemistry rules. These compounds were obtained in high yields and short reaction times. The catalyst could be easily recovered and reused for six cycles with almost consistent activity. The structures of the synthesized azo-linked 2-aryl-quinazolinone compounds were confirmed by 1H NMR, 13C NMR and FTIR spectral data and elemental analyses.

A convenient and metal-free synthesis of vinyloxyimidazopyridine derivatives has been attained via BF3.OEt2 promoted one-pot multicomponent approach. This procedure involves a facile coupling of 2-aminopyridine derivatives with arylglyoxal and alkyne derivatives. BF3.OEt2 complexation has successfully catalyzed the reaction at room temperature. Utilization of transition metal-free catalyst, mild reaction conditions, easy handling and operational simplicity are key features of developed process.

The main aim of this research is the examination of the physicochemical properties and their impact on the electrochemical activity of carbon materials obtained from the starch of different botanical origin (SCs). The obtained materials are compared to graphene nanoplatelets (GNPs) of different particle sizes (5 and 25 µm) applied as an anode active material for high-performance lithium-ion cells. SCs were obtained via thermal carbonization and this process enables an obtainment of better sorption properties compared to GNPs. The excellent electrochemical properties are mainly attributed to the good DLi+ (3.03 × 10−13–7.64 × 10−11 cm2 s−1 for SCs and 7.60 × 10−13–5.42 × 10−12 cm2 s−1 for GNPs) and relatively small resistances (EIS). However, the primary focus is on the specific capacity and cyclability. The capacity retentions of CSC cycled at 1 mA g−1, 10 mA g−1, 50 mA g−1, 1 mA g−1 for 50 cycles are 98%, 99%, 96%, 94% with specific capacities equal to 820, 800, 790, 1000 mAh g−1, respectively. The 5GNPs and 25GNPs may present a much smaller reversible capacity of 650, 600 mAh g−1 at 10 mA g−1. The thermal modification process of starches is simple, safe and widely applied, providing new paths for rational engineering of anode materials for LIBs. Moreover, the applied materials are easily available worldwide and are promising in the well-known Green Chemistry aspect making the cells more biodegradable. Graphic Abstract

Piperidine and δ-Lactam chemicals have wide application, which are currently produced from fossil resource in industry. Production of this kind of chemicals from lignocellulosic biomass is of great importance, but is challenging and the reported routes give low yield. Herein, we demonstrate the strategy to synthesize 2-methyl piperidine ( MP ) and 6-methylpiperidin-2-one ( MPO ) from biomass-derived triacetic acid lactone ( TAL ) that is produced microbially from glucose. In this route, TAL was firstly converted into 4-hydroxy-6-methylpyridin-2(1H)-one ( HMPO ) through facile aminolysis, subsequently HMPO was selectively transformed into MP or MPO over Ru catalysts supported on beta zeolite (Ru/BEA-X, X is the molar ratio of Si to Al) via the tandem reaction. It was found that the yield of MP could reach 76.5% over Ru/BEA-60 in t -BuOH, and the yield of MPO could be 78.5% in dioxane. Systematic studies reveal that the excellent catalytic performance of Ru/BEA-60 was closely correlated with the cooperative effects between active metal and acidic zeolite with large pore geometries. The related reaction pathway was studied on the basis of control experiments.

A single-step microwave assisted digestion (MWAD) procedure employing very dilute solutions of HNO3 was developed for the quantitative determination of bismuth in bismuth-containing pharmaceuticals by hydride generation-atomic fluorescence spectrometry (HG-AFS). Experimental parameters affecting MWAD process such as acid concentration (HNO3), digestion time and temperature were optimized to get quantitative recovery of bismuth. The studies indicated that the method is rapid (within 15 min) including cooling time and recovery > 98% was obtained using 10mL of 5% (v/v) HNO3 as digestion medium with ~0.1g of sample. The optimum microwave digestion parameters obtained were: temperature – 180oC, pressure – 25 bar and hold time - 10 min. A clear solution with negligible residue was obtained after microwave digestion. The digested sample solution was appropriately diluted with 2% (v/v) HCl for subsequent analysis by HG-AFS. The reproducibility, expressed as % RSD was lower than 2% for the allopathic medicine. Under optimal conditions, the limit of detection (LOD) for Bi was calculated to be 0.024mg/kg. The methodology was optimized using a bismuth-containing pharmaceutical – Pylobis, purchased from a local pharmacy. The optimized MWAD approach was further applied to few other bismuth-containing pharmaceutical products. The developed method has significant advantages when compared to the conventional hot-plate digestion methods reported for Bi-containing pharmaceuticals, employing large volumes of concentrated acids. These investigations revealed that the proposed MWAD method in combination with HG-AFS can be utilized for the rapid determination of Bi in pharmaceutical products on regular basis.

An efficient and experimentally straightforward method for the synthesis of 2-amino-4-phenylbenzo [4,5] imidazo [1,2-a] pyrimidine-3-carbonitrile derivatives has been developed via one pot three-co...

The identification of a green, versatile, user‐friendly, and efficient methodology is necessary to facilitate the use of Heck‐Cassar‐Sonogashira (HCS) cross‐coupling reaction in drug discovery and industrial production in the pharmaceutical segment. The Heck‐Cassar and Sonogashira protocols, using N‐hydroxyethylpyrrolidone (HEP)/water/N,N,N′,N′‐tetramethyl guanidine (TMG) as green solvent/base mixture and sulfonated phosphine ligands, allowed to recycle the catalyst, always guaranteeing high yields and fast conversion under mild conditions, with aryl iodides, bromides, and triflates. No catalyst leakage or metal contamination of the final product were observed during the HCS recycling. To our knowledge, a turnover number (TON) up to 2375, a turnover frequency (TOF) of 158 h−1, and a process mass intensity (PMI) around 7 that decreased around 3 after solvent, base, and palladium recovery, represent one of the best results to date using a sustainable protocol. The Heck‐Cassar protocol using sSPhos was successfully applied to the telescoped synthesis of Erlotinib (TON: 1380; TOF: 46 h−1)., Recycle and reuse: Heck‐Cassar‐Sonogashira cross‐coupling using the green N‐hydroxyethylpyrrolidone (HEP)/H2O/N,N,N′,N′‐tetramethyl guanidine (TMG) blend, sulfonate phosphines, and aryl iodides, bromides, and triflates affords the corresponding products in high yield free from metal contamination. The catalyst/HEP/H2O solution can be recycled, increasing turnover number and frequency up to 2375 and 158 h−1, respectively, with a low process mass intensity close to 3 after solvent, base, and palladium recovery. Additionally, Erlotinib synthesis is described.

Cascade reactions appeared as a cutting‐edge strategy to streamline the assembly of complex structural scaffolds from naturally available precursors in an atom‐, as well as time, labor‐ and cost‐efficient way. We herein report a strategy to control cationic cyclization cascades by exploiting the ability of anchoring dynamic substrates in the active site of terpene cyclases via designed hydrogen bonding. Thereby, it is possible to induce “directed” cyclizations in contrast to established “non‐stop” cyclizations (99:1) and predestinate cascade termination at otherwise catalytically barely accessible intermediates. As a result, we are able to provide efficient access to naturally widely occurring apocarotenoids, value‐added flavors and fragrances in gram‐scale by replacing multi‐stage synthetic routes to a single step with unprecedented selectivity (>99.5 % ee) and high yields (up to 89 %)., Cationic cyclizations are one of nature's tools for scaffold diversification. However, these transformations are very difficult to control by chemical catalysts. Herein, a strategy to gain full control over such reaction types is presented by introducing/ breaking specific hydrogen‐bonds inside terpene cyclases. Consequently, valuable flavor and fragrance compounds were produced in gram‐scale within a single enzymatic step in water.

In the last two decades, the investigation of green chemistry processes1 in the protection/deprotection2–3 of functional groups has received much attention. Acylation4–7 of amine and hydroxyl group...

Although transition metal phosphides are well studied as electrocatalysts and hydrotreating catalysts, the application of metal phosphides in organic synthesis is rare, and cooperative catalysis between metal phosphides and supports remains unexplored. Herein, we report that a cerium dioxide-supported nickel phosphide nanoalloy (nano-Ni2P/CeO2) efficiently promoted the C-3 alkylation of oxindoles with alcohols without any additives through the borrowing hydrogen methodology. Oxindoles were alkylated with various alcohols to provide the corresponding C-3 alkylated oxindoles in high yields. This is the first catalytic system for the C-3 alkylation of oxindoles with alcohols using a non-precious metal-based heterogeneous catalyst. The catalytic activity of nano-Ni2P/CeO2 was comparable to that reported for precious metal-based catalysts. Moreover, nano-Ni2P/CeO2 was easily recoverable and reusable without any significant loss of activity. Control experiments revealed that the Ni2P nanoalloy and the CeO2 support functioned cooperatively, leading to a high catalytic performance.

Clean production, as an important part of green chemistry, has received great attention and considerable development in recent years. In this perspective article, we summarized some examples of (nearly) quantitative synthesis, clean separation and purification to emphasize clean production. These reactions were carried out by using eco-friendly solvents and the pure products could be easily obtained through clean procedures.